Anything is possible. Period.
Would you want a blow-off valve in a JRSC application? Only if you've got money growing out of your ass.
Turbo's require blow-off valves because the turbo is placed before the throttle plate, like so:
Air from outside --> Turbo --> Piping --> Throttle Plate --> Engine.
From the time that you life the throttle quickly (like a quick shift, etc), the air compressed by the compressor still travels a distance (dicated by the intake pipe length) before it reaches the throttle plate, which has now closed temporarily. When it does so, the pressure causes this compressed air to return back to the compressor impeller, which is attempting to spin in the 'foward' direction, so to speak. In high boost situations, the air rushing back from the throttle plate (the 'echoed' air) can impart enough force to twist and break the impeller vanes. Bye bye turbo.
The same scenario works for the Vortech centrifugal superchargers as well.
In a JRSC (or any Roots-type blower) application, the flow of air goes a little like this:
Air from outside --> Piping --> Throttle plate --> Supercharger --> Engine
As you can see, the position of the throttle plate
directly affects the amount of air moved by the supercharger. A sudden lift of the accelerator yield nothing more than a sudden drop in air available to be moved by the blower. Simply put.
The bypass valve has nothing to do with any of this BOV nonsense. All the bypass valve does is route air from the supercharger back onto itself, instead of being routed completely into the combustion chamber. By doing so, the engine (including the head, pistons, rings, etc) 'sees' less boost, and essentially is under less load. This, in turn, prevents unncessary stress to be placed upon the engine during times where high pressure is not needed (idle, part-throttle, cruising, decelerating, etc). Any other time, all the air that enters the supercharger goes into the cylinders.
Check
www.jacksonracing.com for a cool animated cartoon of how all this works.